Distant control apparatus.



. IVIANLY C. [VI

v.DISTANT CONROL APPARATUS.

APPLICATIQN FILED JULY|G1909.

Paten-ted may 29, 1917.

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CRLES MATTHEWS MANLY, OF BROOKLYN, NEW YORK.

DISTANZE CONTROL APARATUS.

control apparatus in which a primary control mechanism when manuallyadjusted causes one or more secondary control mechanisms, sltuated atany distance therefrom,

and not having direct mechanical connection thereto, to operate insynchronism My object is to provide simple and effective means in suchmechanisms as that designated, for causing the secondary controlmechanism to move in synchronism with the movements of the primarycontrol mechanism situatedat any distance therefrom, and to remain insuch positions as it has been caused to move to until it is movedtherefrom in synchronism with the primary control mechanism. Anotherobject is to provide means whereby such result may be obtained even whenthe primary control mechanism and secondary control mechanism ormechanisms have motion relative to each other, and my further lobject isto provide means for obtaining this result without direct `mechanicalconnecting parts between the said mechanisms.

With these objects in view my invention consists of a control orsignaling apparatus embodying a primary control mechanism, one or moresecondary control mechanisms i and means for causing the said secondarycontrol mechanisms to operate in synchronism with the operationv of theprimary control mechanism and to remain fixed 1n such positions lasthereby caused to attain until moved therefrom in synchronism with theprimary control mechanism as hereinafter more particularly pointed outin the claims; and my invention further consists in the novelconstruction and details thereof with reference to the accompanyingdrawings, as hereinafter described, and more particularly pointed out inthe claims.

Specification of Letters Patent.

by the screws 11, the

p corresponding cylinder cap,

the same designating numerals refer to the same or corresponding parts`in all the views, the numeral 1 indicates a c linder in which isslidably mounted a plston 2 from one end of which projects a piston rodPatented May se, reir. iApplication filed July 16, 1909. Serial No.508,057.

3, while from the other end projects a piston rod 4, the said rodsbeingfastened to the said piston by the pins 5 and 6 respectively.Closing one end of the cylinder 1 is a cap 7 fastened thereto bythescrews 8 the said piston rod 3 passing through the bore 9 of the cap 7,while the other end of the cylinder 1 is closed by a cap 10 fastenedthereto piston rod 4 passing through the bore 12 of the cap 10.

Formed on the ,piston rod 3 at a point intermediate of its length, is anenlargement 13, thereby providing the two shoulders 14 and 15. Slidablymounted on the rod 3 is a tube 16, provided at one end with an in-lterior flange 17, which slidably fits the rod 3 between the shoulder 14and the'piston 2. Formed at the other end of the tube 16 is an exteriorflange 18, and mounted on the tube 16 is a spring 19, one end of whichacts against the flange 18 and the other end against the piston 2.Similarly on the plston rod 4 is an enlargement 20 providing twoshoulders 21 and 22, and slidably mounted on it is the tube 23, providedwith the interior flange 24 and the exterior flange 25, co-actingwiththe spring 26. The location of the shoulders 14 and 21 and the distancefrom the inner side of the inner lianges of the tubes to the outer sideof the exterior flanges is so chosen with reference to the distancebetween the two cylinder caps 7 and l0 that when the piston 2 is at itsmidpoint the ends of the tubes 16 and 23 preferably minutely contactwith the cylinder caps 7 and 10 respectively. As soon as the piston 2 ismoved the slightest bit to either side of its mid position, the end ofthe tube on that side will act against the thereby causing respectively.

the spring on that side to be compressed, thereby tending to return thepiston to its mid position, and unless acted on by some exterior forcethe piston will therefore tend to remain in its mid position.

Formed on the side of the cylinder 1 is a valve chamber 27, in which areformed the two ports 28 and 29 respectively, and mount# ed in the saidvalve chamber 27 is a valve 30 provided with the four heads"31, 32, 33and 34. In the normal position of the said valve 30 the head 32 coversthe port 28 and the head 33 covers the port 29.

Formed in one edge of the head 32 are small V-notches or slits 35, whilein\the opposite edge of the same head are correspondl ing notches 36,and the head 33 is also provided with corresponding notches 37 and 38The distance between the points of the V-notches on one side of eachhead from those on the other side of the same'head is made equal to thewidth of the port 28 for the head 32, and equal to the width of the port29 for the head 33. Formed in the side of the valve chamber 27 areannular passages 39 and 40, which conr nect the ports 28 and 29respectively," with the pipes 41 and 42 respectively. Formed I in theopposite side of the valve chamber are passages 43 and 44 which areconnected together by the passage 45, the latter finally connecting withthe pipe 46. Formed in the side of the valve chamber between thepassages 39 and 40 is the passage 47 which connects with the pipe 48.

Mounted on the base plate 50 on whichthe cylinder 1 also is mounted, isa'source of fluid pressure supply, which for convenience, 1 have hereillustrated as consisting of a gear pump 51 of the conventional form,but not shown in detail. The pipe 46 is connected to its suctionside andthe pipe 48 to its pressure side, the said gear pump being driven bysome'sourceof power, which for convenience, I have here illustrated,l asa small electric motor 52. Placed at a point intermediate of the lengthof the pipe 46 is a reservoir or tank 53, and connecting the pipe 46 tothe pipe 48 is a pipe 54, in the circuit of which is placed a reliefva'lve 55, here shown as of a conventional form, which permits fluid topass from the pipe 48 to the pipe 46 when the said fluid has reached apredetermined pressure suiiicient to over- 'come the force of the valvespring 56.

'Formed in the side of the cylinder 1 are two passages 57 and 58,through which the two pipes 59 and 60 respectively, are connected totheinterior of the said cylinder, the pipe 59 being continuedl toconnect with the pipe 41 andthe pipe 60 to connect with the pipe 42,previously described. Mounted.

fits the cylinder 1.

fastened thereto by the pins 6 4 and 65 respectively. v

Formed on the' yoke 61 is a in 66 which ts in the slot 67 in one end ofthe link 68, the said link being pivoted to the valve 30 by the pin 69.Formed in the other end of the link 68 is a slotl 70 which co-acts withthe pin 71 formed on the yoke 72 on the rod 73, the said yoke beingprevented from sliding thereon by the collars 74 and 75 secured to thesaid rod by the pins 76 and 77. Projecting from the side of the valvechamber 27 is a bracket 7 8 in the bore 79 of whichI the rod 7 3 isslidably and rotatably mounted. Formed on the side of the cylinder 1 isa bracket 80 .pro-vided with a bore 81 in which. is 'slidably mountedthe bushing 82 the exterior of the said bushing being provided with thekey-way 83 into which the top 84 of the thumb screw 85 projects.A rlhetip of the said thumb screw co-acting with the key-way 83 prevents thebushing 82 from being rotated, but permits it to slide back and forth inthe bore 81 of the bracket 80.

Formed onv the rod 73 are raisedfscrew threads 86 which coact with thescrew threads 87 in the bushing82. The right ,The mechanism justdescribed constitutes what ,I have termed, for convenience, the

primary control mechanism.

fPlaced at anydeslred dlstance from the prlmary control mechanism 1s asecondary control cylinder 101 which for simplicity of adjustment may beidentical in all respects with the primary control cylinder 1 andy inwhichA are mounted parts identical in all respects with thecorresponding parts in cylinder 1. The piston 102 is fitted to thecylinder 101`with as nearly the same degree of frictional resistance asthe piston 2 Similarly the piston rods 103 and -104 fit the bores in thecaps 107 and 110 respectively with the same degree of friction as theircorresponding parts in the primary control cylinder.` The spring 119 isas nearly as possible an exact, duplicate of the spring. 19 and thespring 126 is similarlya duplitate of the spring 26.` Connected to thepassages 157 and 158 in the side of the cylinder 101 are the twopipes159 and 160 respectively, the said pipes connecting through the swingjoint 200 (hereinafter described) with the pipes 59 and 60 respectively,the two latter pipes being prolonged thereto beyond the point where theyconnect with the pipes 41 and 42 respectively, as previously described.

1f the apparatus or device which it is desired to control at a distance,oders only a small resistance to its operation, such operationmay beperformed by the mechanism as now described. Such an apparatus is shownat the right hand end of the 'secondary cylinder.

trol mechanism.

161 which is 't'us or device to ,ary cylinder 101 where the supposedobject 1s `to -swing the pointer 189 to any desired point on thequadrant 190 under the control of theoperator whois situated at theprimary control mechanism at a distance `from thesaid pointer 189. Forthis purpose I attach to the cap 10 of the cylinder 1 an exactly similarquadrant 90 over which the pointer 89 may move, one end of the pointer89 terminating in a ball 91 which is lightly pressed by the spring 92against the end of the piston rod 4, the pointer 189 also terminating atone end in a similar ball 191 which is'alsolightly pressed against thepiston rod 104 by the duplicate spr'ing 192. Protruding from the cap 10of the cylinder 1 is a split collar 93 which may' be clamped to anydesired eX- tent by the thumb screw 94, while protruding from the cap110 'of the cylinder 101 is a similar collar 193 provided with the thumbscrew 194 for clamping it. By means of these clamping collars, anydifference in the friction of motion of the coperating parts of eithercylinder as compared with that of the other cylinder maybe balanced bysuitably adjusting the proper one of these collars.

Where the resistance to operationA of the apparatus or device to becontrolled at a distance is considerable, I find it advantageous toemploy other means, which I.

will now describe, rather than to impose on the-piston rod of theprimary control cylinder a frictional resistance equal to thatencountered by the piston rod of the second- This is especiallyadvantageous where the resistance of the apparabe controlled is veryheavy and is imperative where the said resistance iiuctuates, the degreeof such fluctuations being usually unknown to the operator who thereforecannot adjust the friction of the primary control mechanism tocorrespond with that encountered by the secondary con- Mounted on thepiston rod 103 is a yoke prevented from sliding thereon bythe collars162 and 163 and the pins 164 and 165. lProjecting from the yoke 161 is apin 166 which fits in the slot 167 in the end of the link 168. The link168 is pivoted at its center by the pin 169 to the valve 130, the otherend of the said link terminating in a slot 170 which ts around the pin'171 which projects from the yoke 300 or whatever form lof part it isdesired to move to effect the desired distant control. Assuming,however, that the yoke 300represents such a part as it is desired tomove to control some apparatus of which it is a part, the said yoke 300is secured to the piston rod 301 between the nuts 302 and.303, the otherendiof the said piston rod 301 terminating in-.the piston 304 which ismounted .opposite sides of each cylinder and the "fined with a Huid,

Vpressible one,

yif the closed by the heads those formed in the valve 30, the distancebetween the points of the V-notches on the head being just equal tothewidth of the chamber 127 are the three passages 143, 144 and 147, towhich are connected the pipes 145, 146 and 148, respectively. Formed onthe side of the valve chamber 127 is the bracket 178 provided with anarm which reaches over to, and forms a support for the' cylinder 101,thus maintaining the said valve chamber 127 at their proper relativepositions. f

The operation of the device is as follows:

Assuming all the ports and passages of the primary control mechanism, aswell as the cylinder.101 and its connecting pipes, of the secondarycontrol mechanism, to be preferably a non-comsuch as oil or water, and areserve supply to exist in the reservoir 53; gear pump 51 be rotated bysome such source of power as the electric motor 52, and in such adirection as to cause the gear pump to force out fluid into 'the pipe 48and to draw it in through the pipe 46, with the parts in the positionshown, the ports of -the control valve chamber 27 being of the valves30, pressure will rise in the pipe 48 until finding no egress it raisesthe blow-oil' valve 55 against the spring 56, permitting the eX- cessfluid t'o blow off at such a pressure back into the suction side of thepump, thereby short circuiting the Huid, but so long as the gear pump iskept in motion the pressure in the pipe 48 will remain constant at theamount necessary to keep' the relief valve 355 blowing ofi". With thispressure 'existing in the pipe 48, if the operator now moves the rod 73longitudinally either by pushing or pulling on it, or by tion of thecontrol rod 73 will cause the coacting end ofthe link 68 to be moved inthe same direction, and the said link fulcruming at its other end on thepin 66 will cause the control valve 30 to be forced in the samedirection. Assuming that such displacement of the rod 73 is toward theleft, the control valve 30 will be displaced toward the left, therebyuncovering the port 28 and permitting fluid pressure from the ,pipe 48to pass through the ll-notches 36 into the said port'28 and from thenceports 128 and 129 re-l' spectively. Formed in the side of the valverotating it in the bushing 82, such mothrough the pipe 41 and pipe 59into the left hand end of the primary control cylinder 1. Such fluidpressure passing into the left hand end of the cylinder 1 will act onthe piston 2 to force it to the right and in forcing it to the rightwill compress the spring 26 vin proportion to the extent that the saidpiston moves in this direction. As soon, however, as the piston 2 movestoward the right it will pull the piston rod 3 in the same directionthereby, through the yoke 61 and pin 66, causing the lower end of thelink 68 to be moved in the same direction and the upper end of the saidlink 68 fulcruming on the pin 71 will cause the control valve 30 to beforced toward the right until the head 32 again covers the port 28. Atthe same time that the piston 2 moves toward the right the piston rod 4will force the lower end of the pointer 89 in the same direction,thereby causing the other end of the pointer to move toward the left orin a counter-clockwise direction with reference to the quadrant 90. Atthe same time that the ii'uid pressure, admitted through the controlvalve 30 into the pipe 41, passesl into the pipe 59 and from thence intothe left hand end of the primary control cylinder 1 the same iuidpressure also passes through the pipe 59, the swing joint 200 and thepipe 159 into the left hand end of the secondary control cylinder 101,the frictional resistance to motion having been adj usted to equalamounts in both the primary and secondary control cylinders, aspreviously explained, and the corresponding springs in the saidcylinders being of equal stiffness, the piston 102 in the cylinder 101will be forced to the right at the same time, and to exactly the sameamount that the piston 2 is forced to the right in the cylinder 1, andthe piston rod 104 acting onthepointer 189 will move the upper end of itin the same direction on the quadrant 190 and to the same amount thatthe pointer 89 was moved on the quadrant 90 y the action of the primarycontrol piston rod. At the same time that fluid pressure passes throughthe .pipe 41 and pipes 59 and 159 into the left hand ends of thecylinders 1 and 101 respectively any liuid expelled from the right handend of the said cylinders 1 and 101 is free to pass through.

the pipes 60, 160 and 42 into the port 29 and from thence through thenotches 38 into the passages 44 and 45, and from thence through the pipe46 into the reservoir 53, and onv the supposition that all the ports,passages and cylinders were filled with fluid to start on, exactly thesame amount of fluid would be returned to the reservoir as was takenfrom the high pressure pipe 48, the total quantity in circulationremaining constant. Similarly, if the rod 73 lbe moved toward the right,the cons ome source of matteo trol valve 30 will be moved toward theright, thus permitting duid pressure to pass from the pipe 48 throughthe notches 37 into the port 29 and from thence through the pipes 42,60and 160 into the righthand end of the cylinders l and 101, and thepistons 2 and 102 will be thereby simultaneously moved to the left untilthe motion of the piston 2 to the left acting on the link 68' pulls thecontrol valve 30 back to its, neutral position, thereby shutting 0E theadmission of further fluid pressure to the cylinders. It is thus seenthat the motion of the primary control piston and its piston rod notonly move in a direction determined by, and to an extent proportionalto,

the movement of the primary control valve,

sion Aof uid unless the control valve be' further moved by the operator,but the piston is locked in this position, since no fluid pressure caneither pass into or out of the cylinder without further manual operationof the primary control valve. It the amount of force required to operatethe lapparatus which it is desired to control at a distance is verysmall the device as now described in its operation is suiicient,'for theoperator may by moving his control rod 7 3 bring the pointer '89 to anydesired point on the quadrant 90 and thereby cause the pointer 189 to bemoved to an exactly corresponding position onthe quadrant 190, no matterwhat the distance which separates the primary control mechanism from thesecondary control -mechanisnr If, however, the resistance to operation,of

the device to be controlled at a distance be considerable, andespecially if it vary in amount from time to time, or cause reactions onthe secondary control piston, the apparatus as just described in itsoperation would tance may be eii'ected by power derived from suchsecondary source and thereby prevent either reactions on, or variationsin the resistance encountered by, the secondary control system.

When used in this way the operation of the device is as follows:

supposing the ipe 148 to be connected to uid pressure supply (not shown,but which may be a duplicate of the gear pump 51 driven by a duplicateof the electric motor 52, if desired) and the pipes 145 and 146 to beconnected together and to 4 the suction side of such secondary source ofiiuid pressure supply, uid pressure will exist in the valve chamber 127between the heads 132 and 133, and supposing, as previously explained,that the yoke 300 represents a' part of the apparatus to be controlledwhere the resistance to motion is either variable or considerable inamount or both, any movement of theJ primary control rod 73 will causecorresponding movement of the pistons 2 and 102 and such motion of thepiston 102 through its rod 1.03 will act on the lower end of the link168 and thereby cause the secondary control valve 130 to be moved in thesamev direction as the-piston 102 and to a corresponding amount. If thepiston 102 moves toward the left, the port 129 will be uncovered by thehead 133 permitting iu'i-d pressure to pass into the left hand endy ofthe cylinder -305 where it will act against the piston 304 and force' ittogether with the yoke 300 to the right until such motion of the iston304 actin on the upper end of the link 168 causes the secondary controlvalve 130 to be moved to its neutral position, thereby shutting off theadmission of further Huid pressure, and since at the same time theexhaust of Huid from the right hand side of the piston 304 is shut offby the i valve head 132,the piston 304 will be locked in such positionas it has been moved to until again moved -by fluid pressure admitted bythe secondary control valve 130. y

Similarly motion of the'secondary control piston 102 to the right willcause the secondary control valve 130 to be moved to the right, thuspermitting fluid prcssureto pass into the right hand end'of the'cylinder 305, thereby forcing thel piston 304 to the left until suchmotion of it returns the secondary `control1va1ve 130' to its neutralposition. It

is thus seen that lbyusing the 'secondary'control mechanism, as f at rstdescribed, merely for the operation of the secondary control valve, theresistance'vmotion of which can be made as small and as constant asdesired,

. and using a secondary source of power for effecting the adjustment lofthe p'art'which it is desired to operate at a distance, the

tsbe

movement of the said part -at a distance may keptl in absolutesynchronism with the 1 motion of the primary control mechanism.

fcc

In some applications of the above described mechanism, I' have found itnecessary to provide means for enabling the sec- 'ondary controlmechanism as aunit'to have motion relative` to the primary controlmechanism or vice versa. lOne of the specialv l cases of this kind hasbeen where the primary control mechanism was situated on-a part whichhad a motion. of rotation 4with reference to the secondary controlmechanism. In such cases I employ the swing joint 200 which is shown indetail on an enlarged scale in Fig. 2. The pipes 59 and 60 are eachconnected to the lower plate 201, the pipe 59 through the passage 202being connected with the circular channel 203 formed in the said plate201, while the pipe 60 through the passage 204 is connected with theouter circular channel 205 formed in the said plate 201. The p'ipe 159is likewise connected by the passage 206 to the inner circular channel207, while the pipe 160 through the passage 208 is connected to theouter circular channel 209, both formed in the lower face of the plate210. The two plates 201 and 210 are held together by the two guard rings211 and 212 fastened to each other by the screws 213,the plates 201 and210, however,- being free to rotate with reference to each other. Formedin the center of the two pla-tes are the bores 215 and 216 respectively,

through which a central plug or any other desired part may be passed. Itis readily seen that bythis means the primary control mechanism and thesecondary control mechanism will perform their functions properly evenwhen one possesses motion with respect to the other.

In turning up the primary and secondary control mechanisms so that themotion of the primary piston and secondary piston will be in exactsynchronism, I find it advantageous to ma e the resistance encounteredby the Huid pressure in passing to the secondary control mechanism asnearly as possible the same as that encountered in passing from theprimary control valve to the primary control cylinder, and the morenearly the two mechanisms are required to work in synchronism the morenearly all the parts and conditions in one mechanism should beduplicates of, or properly. proportioned to, the corresponding parts andconing inthe bracket 49 of the base plate 50 and lsecured tothe saidpiston rod. is a gear wheel' 95 which meshes with a pinion 96 mounted onthe shaft 97 of the gear pump' 51. Similarly the piston rod 103 isextended tothe left and given a bearing in the bracket 178 and secured'to the piston rod is a gear wheel 195 meshing with a pinion 196 securedto the shaft 197 which is journaled in the ends of the brackets 178 and198. Whenever the gear pump 51 isl rotated to generate vto get out ofmesh with the pinion 96. Similarly assuming the shaft 197 to be given amotionof rotation from' some external source of power, not shown,whenever the secondary: control mechanism is at Work the 4pinion .196through the gear 195 will cause the secondary control piston 102 torotate, and I have found that when such motions Aof rotation are givento the pistons of the control cylinders, even though the motion be verysloW lthe starting friction of the pistons and rods with reference tolongitudinal motion is practically eliminated, the friction beingpractically constant at all times.

Referring again to the bushing 82 mounted in the bracket 80 of theprimary control mechanism and to the screw threads 86 of the primarycontrol rod 7 8 coperating with the internal threads 87 of said bushing82, l have found the arrangement of parts there shown enables the oerator to have a very complete control o the primary control valve. Byadjusting the thumb screw 85 so that the shoulder formed by thereduction in diameter of the tip is brought against the side of thebushing 82 the friction to sliding of the said bushing 82 may beadjusted to any amount desired, and when the operator desires rapidadjustments of the control valve 30', he may obtain the same by pushingor pulling on the rod 73fby means of the knob 88, thus sliding thebushing 82 longitudinally in the bracket 80, while if minute adjustmentsof the primary control valve 30 vbe desired, adjustments to the minutestfraction of an inch may be obtained by turning the knob 88 therebyadvancin the rod 78 through its screw threads 86 an the internal threadsof the bushing 82, the said bushing 82 acting as a fulcrum for thescrew,

since the tip 84 of the thumb screw 85- in the key-way 83- prevents thesaid bushing from turning while the shoulder on the said thumb screwcreates suflicient friction of thel bushing in the bracket to cause therod 73 to advance rather than the bushing 82 to be moved. By this meansit is possible to make 'either micrometric or rapid adjustments of thecontrol valve, and thereby maintain either a micrometric or rapidcontrol of the distant object, whereas the operation of the control rodby means of screw adjustments alone, while giving micrometric control,.

would prevent rapid control, and Ithe operation of the said control rodby pure sliding action alone would give rapid control, but make itimpossible to get micrometric conl inatteso trol, since it ispracticallyv impossible to manually slide a rod either steadily, slowlyor to a minute amount, and as such a combination of micrometric andrapid control by one operating element is believed to 'be a new andvaluable improvement in the art, ll shall claim it broadly.

Connected to the pipe 59 just above the point where it is joined by thepipe 41 is a pipe 99, and connected to the pipe 60 just above the pointwhere it is joined by the pipe 42 is a pipe 100, the said pipes beinghere shown as broken, but intended to be prolonged to connect to anothersecondary control cylinder, similar in all respects to the cylinder 101should it be desired to con- *80 trol a second distant object insynchronism with the movements of the primary control mechanism, anditis readily seen that should it be desired to control still otherdistant objects it canbe readily done by providing other secondarycontrol mechanisms similar in all respects to that here shown andplacing them at each of the objects to be controlled, all ofv theI saidsecondary control mechanisms being connected to the main control pipes59 and 60.

The control system above described is not only applicable underconditions where .it is impossible to obtain a direct mechanicalconnection (by direct mechanical connection, l mean, a connectionthrough rotatable or slidable rods, shaft, gears or similar elements)but also in conditions Where the maintenance of such mechanicalconnection involves the use of 'a considerable number of intermediateparts, such as gears, levers, etc. for going around corners, the presentsystem is freer from lost motion introduced by the gears, joints, etc.than in the direct mecahnical connection. 105

llt is furthermore seen that by means of the control mechanism heredescribed, it is possible to adjust the distant object to' any positionbetween its maximum position on one side of some imaginary vzero to thesame 'or some other maximum position on the other side of the said zero,therev being no steps in the adjustment, which is perfectly continuousand smooth -at all points. l

- rlihe primary control mechanism as herein described, constitutes whatmay be termed -for convenience a follow-up controller, in

that the movements of the primary control piston are not only in exactsynchronism With the movements of the manually operated control rod, butthe primary control acting on it or through leakage of the Huidoperating in synchronism with said power held between it and the primarycontrol valve, such change in position of the` primary control pistonautomatically moves the primary control valve which admits fluidpressure which sends the said piston to the point where it` should be,the position of theprimary control rod.

I have previously stated that the fiuid circuits of the mechanism arepreferably filled with oil or water. I find that the use of such apractically incompressible fluid gives a more accurate control thegreater its degree of incompressibility, ordinary grades of machine oilgiving especially good results when the circuits are free from air,which otherwise results in the formation of air bubbles in the oil,rendering it quite compressible.

Claims:

l. Av control mechanism comprisin an element movable by power toanyposition within its range of movement, a source of hydraulic power, amanually movable element having no mechanical connection thereto butcontrolling the movements of the said power movable element and meansfor causing said hydraulic power to oper-l ate said power movableelement to move in exact synchronism with the movements of 'saidmanually movable element.

2. The combination of a primary control mechanism comprising a manuallyoperatable element and a power operatable element, a source of hydraulicpower `for operating said element, a secondary control mechanismcomprising a power operatable element, and means lfor causing both thesaid power operatable elements to be moved in synchronism with themovements ofthe manually operatable element.

3. The combination of a source of hydraulic power, a primary controlmechanism embodying a manually operatable control element and a memberoperated by said source of power under control of said element,l meansfor causing said member to move in exact synchronism with said manuallyoperatable control element, a secondary control mechanism also operatedby said source of power under control of said primary control mechanism,and means for causing said secondary control mechanism to also move inexact synchronism with said 4manually operatable control element.

4. The combination of a primary control mechanism comprising a manuallyoperatvable element, a source 'ofl hydraulic power and a poweroperatable element operating in synchronism with said manuallyoperatable element, a secondary control mechanism operatable element andmeans for maintainmg synchronism of operation between the said primaryand said 'secondary mechaas indicated by 'i and having no mechanicalconnection thereto,

a power operatable control element, a source of hydraulic power foroperating said element, and means for causing the said object to move inexact and continuous synchronism with motions of the said manuallyoperatable element. v

7. The combination of a manually operatable control element, a poweroperated control element separated from and having no mechanicalconnection to said manually operatable element, a source of hydraulicpower for operating said element and means for causing the said poweroperated control element to operate in continuous synchronism with theoperation of the said manually operatable control element.

8. The combination of a manually operatable control element, an objectseparated from and having no mechanical connection thereto, a poweroperatable control element,

a source of hydraulic power for operatingV said object and element andmeans for causing the said object and the said power operatable controlelement to operate in continuous synchronism with the manuallyoperatable control element.

9. The combination of a manually operatable control element capable ofcontrolling power a hydraulic power operatable control element capableof controlling hydraulic power, an object separated from and having nodirect mechanicalI connection to said manually operatable element, asupply of hydraulic power and means for causing said object to be movedby power in continuous synchronism with movements of sald manuallyoperatable control element.

10. The combination of a manually opertatable control element, a poweroperatable element, means for causing said manually operatable elementto control the'movements of said power operatable element and means formaintaining the frictional resistance to movement of the said poweroperatable element the same at the beginning of its movement as at otherperiods thereof.

11. The combination 'of an object, a manually operatable element, ahydraulic power mechanism for moving said object yon which considerableforces are acting element comprising means for moving said' object bypower in continuous synchronism with motions of the said manuallyoperatable element, 'and means for causing said object to locked in itssynchronized position when sand manually operatable clement isv l@ not1n motion.

' CHARLES MATTHEWS MANN.

Witnesses:

R. C. MTCHELL, CHAs. A. PEARD.

